It has become increasingly difficult to generate and distribute short duration clock pulses on a large scale, for large scale high-speed memories. Such pulses have been required for equalization of the bit lines, etc., but the provision for such pulses prolongs access times and degrades performance of the memory. A current-mode read data path, however, eliminates the need for such clock pulses. Several amplifiers have been described in the literature, but the use of positive feedback to reduce the amplifier input resistance has limited the use of this type of amplifier to single-ended, single stage applications.
A description of a current-mode data path for an SRAM was published in the Apr. 19, 1991 edition of the IEEE Journal of Solid State Circuits. The paper, "Current-Mode Techniques For High-Speed Real Side Circuits", by E. Seevnick, et al., proposes the use of two complementary current amplifiers as local and global sense amplifiers in an SRAM data path. The detailed design of these amplifiers is, however, different from the amplifier of the present invention. Another paper, "Fast CMOS Current Amplifier And Buffer Stage" by Temes and Ki describes a similar single stage current amplifier.